A simple room temperature synthesis of MCM-41 with enhanced thermal and hydrothermal stability

Highly ordered mesoporous silica samples were synthesized in less than 3 h using a simple synthesis methodology at room temperature with surfactant to silica ratio 0.1, using sodium silicate as a source of silica and cetyltrimethylammonium bromide (CTAB) as structure directing agent. Powder X-ray diffraction and N2 adsorption studies exemplified addition rate of sodium silicate solution is critical on the final properties of the materials. Remarkable thermal and hydrothermal stabilities of the samples prepared through this route were seen in contrast with the conventional methodology. Optimization of conditions surmised HCl as neutralizing agent and silicate addition time of 10 min is appropriate for obtaining a well crystalline and stable material. Slower rate of silicate addition might have facilitated better condensation of oligomeric silica on the preformed silica-surfactant aggregates responsible for such high thermal and hydrothermal stabilities. Development of such simple and easily expandable methodologies for these mesoporous materials will pave ways for their practical applications.